User`s manual

User’s Manual
GSM35 21 RTD Finland Oy
SIM-card reader
Standard 3V and dual voltage SIM-cards can be used with the GSM35.
Older 5V SIM cards will not work, though they may operate in standard
GSM cellular phones. These new 3V SIM cards are no older than two
years. The SIM-card holder has a card detection circuit that will in theory
allow hot insertion and removal of the card. This is
NOT
recommended,
since the SIM card contenets can become corrupted if it is removed while
the TC35 GSM modem is writing to it.
A very useful AT command that shows detestion of the SIM card is:
AT^SCID
. The SIM card identifier is given as a reply
^SCID: value
shows
the ID of the SIM card. If no ID is detected the TC35 can not read the SIM
card and can not connect to the GSM service provider network.
To add an entry to your SIM card you may use the AT+CPBW command.
In this example we add the RTD Finland phone number [phone]
to the SIM card memory location “1” with the following AT command set:
AT+CPBW=1,35893464538,145,RTDFinland
AT+CREG?
Will indicate if the GSM35 is logged into the network. If the
reply for example is
+CREG: 0,1
it means that connection to the home
network is valid. A complete AT-instruction set documentation is included
in the TC35 user’s manual.
UART serial port circuitry
GSM data is sent and received through a standard 16C550 compatible
UART. All today’s operating systems will recognize and support this serial
communication device. The GSM35 uses its own onboard serial port and
will not reserve serial port resources from the system. The I/O base
address and interrupt for this serial port can be flexibly set as has been
described in previous chapters of this manual. This user’s manual will not
wade into details of serial port programming. This information is
commonly available today. You can use any communication software
package or terminal program to connect to your GSM35 UART. Just make
sure you set up the I/O and IRQ are set right. The correct terminal speed
for AT commands is 9600 baud, 8 databits, no parity, one stopbit, and
hardware handshake. The UART on the board is specified for full
operation from –40 to +85C. The oscillator frequency is set to be
1.8432MHz. Note that the UART interrupt can be disabled or enabled
from software by writing to bit 01 in address BASE+0x402.